Most suppliers of telephone services offer their subscribers a service of displaying the call number. Thus, when a call is displayed on the terminal of a subscriber, the latter may know the caller's number. This information is often used by the terminal to deduce the name of the caller from a search in an address book.
With the expansion of the Internet, there is today a steep increase in the number of cases of identity spoofing. Cases of spoofing telephone numbers or email addresses are particularly frequent and greatly facilitated by current technologies. For example, in order to circumvent the filtering of hidden numbers and to encourage correspondents to respond, some unscrupulous call centers insert a number of a third party in the caller number field. These call centers sometimes insert the number of a subscriber geographically close to the person to be reached in the caller number field, so that the number displayed seems familiar to them, thus encouraging them to respond. The number thus inserted may be changed regularly so as not to arouse suspicion among the operators.
In other cases, the spoofer sends their victim a message by pretending to be a trusted organization, e.g. a well-known public or private organization so as to encourage the victim to reveal personal information, such as login IDs or a credit card number.
There are also paid online services that enable a communication to be established to a correspondent while displaying a telephone number freely chosen by the caller.
Communication over IP services do not have physical criteria for certifying the caller number displayed by a subscriber as is the case with a PSTN (Public Switched Telephone Network) or ISDN (Integrated Services Digital Network) line. This phenomenon will continue to spread since it is very simple for unscrupulous persons to configure any caller number in a VoIP communication. In fact, more and more communication solutions enable users to configure their telephone number themselves without any check being made. For example, there are WebRTC communication solutions interconnected with the PSTN or IMS (IP Multimedia Subsystem) network, which can be used to enter caller numbers without any real possibility of checking.
There are solutions for verifying the validity of a caller number inserted by a PBX (Private Branch Exchange) connected to a PSTN network, e.g. the solution described in patent application U.S. Pat. No. 5,953,399 A. Here it is a matter of verifying that the number inserted in the call signaling by the PBX correctly corresponds to a number associated with the PSTN line. Patent application US 20070127658 A1 also provides a solution based on a comparison of the caller number inserted in the signaling and the number associated with the corresponding PSTN line. Although these solutions are effective in a context of interconnection with a PSTN network, they are of no use for curbing fraud in an all IP (Internet Protocol) system.
Since spoofing a telephone number may be fraught with consequences for the subscriber whose number is spoofed, there is a real need for a solution aimed at protecting subscribers from these practices, particularly in the context of communications over IP.
The present invention improves the situation.